JPH08217712A - Production of phenol - Google Patents

Abstract

PURPOSE: To obtain phenol in high selectivity and in high yield by using a simply obtainable catalyst standing repeated uses, prepared by supporting ions of a specific element on a zeolite. CONSTITUTION: (B) Benzene is reacted with (C) dinitrogen oxide in the presence of (A) a zeolite supporting ions of at least one element selected from the element group comprising elements of the group IIIB and transition metal elements of the periodic table to give (D) phenol. In the zeolite, one having the ratio of SiO2 /Al2 O3 of 10-200 is especially preferable. Gallium and copper are preferable as the element for the element ions. The amount of the element ions is in the weight ratio of the weight of the zeolite (weight after baking at 400-550 deg.C in air for two hours) and that of the element ions of 100:0.01 to 100:5, especially 10:0.05 to 100:0.2.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the oxidation of benzene,
The present invention relates to a method for producing phenol, which is widely used as a raw material for synthesizing various chemicals, and more specifically, to a method for producing phenol using a catalyst having high selectivity and stable activity.

[0002]

2. Description of the Related Art Conventionally, the cumene method has been mainly used as a method for producing phenol, but this method produces acetone as a by-product. However, due to the excessive supply of acetone in recent years, the price advantage of the cumene method is being lost. Therefore, it has been desired to develop a method for producing phenol that does not produce acetone as a byproduct.

As a method for producing phenol which does not produce acetone as a by-product, a direct oxidation method of benzene by a gas phase reaction (direct acid method) is known. As the oxidant, oxygen (for example, Japanese Patent Laid-Open No. 1-211540), water (for example, Japanese Laid-Open Patent Publication No. 2101034), or dinitrogen oxide (N ₂ O) (US-5110995, Japanese Patent Laid-Open No. 2-11531, Japanese Patent Laid-Open No. 58-146522 ) Is mainly used. Of these, nitrous oxide is a very effective oxidant because it can selectively synthesize phenol in a one-step reaction and the by-product is also nitrogen (N ₂ ). The catalyst for synthesizing phenol by the benzene direct acid method using dinitrogen oxide contains vanadium oxide as a component (JP-A-58-146522), or
ZSM-5 type zeolite is known. ZSM-5 type zeolite is H ⁺ type by ion exchange (Japanese Patent Laid-Open No. 2-1153
It has been reported that 1), or one containing an iron atom in the zeolite lattice prepared by hydrothermal synthesis (US-5110955) is effective as a catalyst. However, it was not known at all that the ZSM-5 type zeolite carrying metal ions by ion exchange was effective.

[0004]

When the above-mentioned catalyst containing vanadium oxide is used, the reaction temperature is 550.
It is necessary to raise the temperature to about 0 ° C., and the selectivity is low at about 50%. Moreover, in order to maintain this selectivity, water vapor must be entrained in the reaction gas, which is industrially disadvantageous. Further, even among ZSM-5 type zeolite, H ⁺ type has a problem that the selectivity of phenol is low and the activity is lowered. There is also a problem that the activity decreases when regenerated and used. Furthermore, even ZSM-5 type zeolites containing iron atoms in the lattice are synthesized by hydrothermal synthesis, which usually takes several days, and there is a problem in supply when used in large quantities on an industrial scale. . There is also a problem that the reproducibility of the catalytic activity is poor. The present invention solves these problems, has a high selectivity, and is capable of producing phenol in a stable yield, a catalyst can be easily produced, and is highly industrially advantageous in the production of phenol by enduring repeated regeneration. The purpose is to provide a method.

[0005]

Means for Solving the Problems The present inventor has found that when a catalyst in which ions of a specific element are supported on a zeolite is used, the selectivity of phenol is high, and the yield is stable without lowering the catalytic activity. It has been found that phenol can be produced. That is, the present invention is based on the periodic table 3B.
A method for producing phenol, which comprises reacting benzene and dinitrogen oxide in the presence of a zeolite carrying ions of at least one or more elements out of a group of elements consisting of group elements and transition metal elements Is.

As the zeolite used in the present invention, commercially available zeolites such as Y type, L type, mordenite, ZSM-5 (MFI) type and the like can be used. The SiO ₂ / Al ₂ O ₃ ratio in these zeolites is 3 to 400, and especially ZSM-
In 5, the composition of 10 to 400 can be used.
Among this, the activity is preferably high points are ZSM-5, in particular SiO ₂ / Al ₂ O ₃ ratio is preferably from 10 to 200.

Ions of the elements supported on the zeolite include gallium (Ga), indium (In), and boron (B).
And ions of transition metal elements such as cobalt (Co), nickel (Ni), copper (Cu), platinum (Pt), and palladium (Pd). Among these, gallium, indium, and copper ions are preferable because of their high yield, and gallium and copper are particularly preferable.

The amount of ions of these elements carried is such that the ratio of the weight of zeolite (weight after firing in air at 400 to 550 ° C. for 2 hours) and the weight of element ions is 100: 0.01 to.
100: 5 is preferable, and in consideration of conversion and selectivity, the ratio is more preferably 100: 0.05 to 100: 0.4, and most preferably 100: 0.05 to 100 :.
It is 0.2.

As a method for supporting the above-mentioned ions, any of a usual impregnation method, an ion exchange method, a mechanical mixing method and the like can be used. In this case, it is more preferable to bake in an atmosphere containing oxygen after impregnation, ion exchange or mechanical mixing. The firing temperature is 350-
650 ° C, particularly preferably 400 to 550 ° C. After these treatments, heat treatment may be performed in vacuum. In the ion exchange method, for example, calcined zeolite is added to a water bath solution of gallium nitrate or indium nitrate, left to stand in the temperature range of room temperature to 95 ° C for about 1 hour to 3 days, filtered, washed, and then 400 to Bake at a temperature of 550 ° C. In the impregnation method, for example, gallium ions or indium ions are added by adding zeolite to an aqueous solution of gallium nitrate or indium nitrate, evaporating the water, and then calcining this in air or an oxygen stream at 400 to 550 ° C. It can be supported as these metal salts.

In the present invention, before or after supporting the ions of the above-mentioned elements on the zeolite (preferably before supporting), the zeolite is converted into H 2 by an ion exchange method.
It is preferable to convert to ⁺ type or a part of H ⁺ type. This ion exchange is performed by adding the calcined zeolite to an aqueous solution of ammonium nitrate or ammonium chloride, for example, at room temperature to 95 ° C.
After leaving it in the temperature range of 1 hour to 3 days, filter it,
It can be carried out by calcination at a temperature of 400 to 550 ° C. after washing.

According to the above, the zeolite carrying the ions of the above elements is used as a catalyst after being pretreated at a temperature of 350 to 400 ° C. in a stream of nitrogen, dry air or oxygen prior to the reaction. The form of the catalyst at the time of reaction is not particularly limited, and for example, a powder as it is or a molded form can be favorably used. In the case of molding, it is possible to use a binder such as silica gel.

The reaction between benzene and nitrous oxide is carried out by contacting benzene and nitrous oxide in the presence of a catalyst, preferably in the gas phase. This reaction can be carried out in a batch system, but industrially, a gas phase flow system is preferred. The reaction temperature is 250 to 450 ° C, preferably 300 to 400 ° C.
This is because if the reaction temperature is too low, the conversion rate of benzene is small, and if it is too high, side reactions easily occur. The supply amount of benzene is 0.1 to 10 kg / hr, preferably 0.
It is 5 to 5 kg / hr. The supply amount of nitrous oxide is 1 / 0.2 to 1/20, preferably 1 / 0.5 to benzene / dinitrogen oxide molar ratio.
It is 1/10. If the amount is larger than this, the reaction proceeds, but side reactions and deactivation of the catalyst become large, which is not preferable.

If necessary, an inert gas such as nitrogen gas or helium gas can be used as a diluent or carrier. The ratio of inert gas at this time is 1 ~
It can have any value between 99% by volume.

[0014]

In the present invention, it is not always clear what kind of function in the catalytic reaction the loading of the element ions on the zeolite plays. However, in the conventional reaction using zeolite, it is considered that coke is deposited on the surface of the zeolite as the reaction progresses, resulting in a decrease in activity and selectivity. When a group element is supported, the coke adhering to the zeolite is easily desorbed even at low temperatures, so the coke produced on the zeolite surface during the reaction is
The inventor believes that the amount can be kept small.
On the other hand, when the transition metal is supported on zeolite, the inventor believes that due to the oxidation reaction, even if coke adheres to the zeolite surface during the reaction, it is immediately oxidized.

[0015]

EXAMPLES The present invention will be specifically described with reference to the following examples. Example 1 As described below, gallium ions were supported on zeolite by an ion exchange method and used as a catalyst in the reaction. First, as a zeolite ZSM-5 (SiO ₂ / Al ₂ O ₃ = 17)
(Manufactured by Mizusawa Chemical Co., Ltd.) was calcined in air at 400 ° C. for 2 hours. In an aqueous solution of ammonium nitrate (ammonium nitrate 1.
(00 g was dissolved in 300 ml of ultrapure water) and 4.00 of this ZSM-5 was added.
g and heated at 80 ° C. for 2 hours with stirring. After cooling to room temperature, it was filtered and washed with ultrapure water. Further, it was calcined in air at 550 ° C. for 2 hours.
After cooling and pulverizing, it was added to an aqueous solution of gallium nitrate (a solution of 0.028 g of gallium nitrate n-hydrate (0.004 g of gallium ions) dissolved in 300 ml of ultrapure water) and stirred at 80 ° C for 2 hours. After allowing to cool to room temperature, it was filtered and washed with ultrapure water.
Then, it was baked in air at 400 ° C. After calcination, it was molded by using a tablet molding machine, crushed, and having a particle size of 1 mm to 710 μm was used as a catalyst. 1 g (2 ml) of catalyst was packed in a glass reaction tube with an inner diameter of 12 mm, and a mixed gas of helium and oxygen (volume ratio 80
/ 20) Heat treatment was carried out at 400 ° C for 2 hours in an air stream. Then
Switch to nitrogen gas and lower the temperature to 350 ° C, then add nitrous oxide 24 ml / min, benzene 4.93 g / hr, nitrogen 20 ml.
The reaction was performed while supplying each at a rate of / min. The selectivity was calculated by the following formula. Selectivity = phenol produced (mol) / (feed benzene-
Recovered benzene (mol)) This selectivity remained above 99% during the reaction. Also, the rate of phenol formation in this reaction is shown in the table.

[Comparative Example 1] ZSM-5 (SiO ₂
/ Al ₂ O ₃ = 17) was calcined in air at 400 ° C for 2 hours. Add 4.00 g of this ZSM-5 to an aqueous solution of ammonium nitrate (1.00 g of ammonium nitrate dissolved in 300 ml of ultrapure water),
Heated at 80 ° C. for 2 hours with stirring. After cooling to room temperature, it was filtered and washed with ultrapure water. Further, it was calcined in air at 550 ° C. for 2 hours. After cooling and crushing, mold using a tablet molding machine, crush, particle size 1mm
A catalyst of ˜710 μm was used as a catalyst. After that, the reaction was performed in the same manner as in Example 1. The selectivity was 42% for 0 to 1 hour after the start of the reaction, and the selectivity increased thereafter, but 82% was not sufficient for 2 to 3 hours.

Example 2 In place of the introduction of gallium ions by the ion exchange method shown in Example 1, gallium nitrate n
The reaction was performed in the same manner as in Example 1 except that 0.028 g of the hydrate was carried by the impregnation method and calcined at 400 ° C. During the reaction, the selectivity was maintained at 99% or more. Table 1 shows the rate of phenol production at that time.

Example 3 In place of the introduction of gallium ions by the ion exchange method shown in Example 1, 0.0114 g of copper acetate was used.
The reaction was carried out in the same manner as in Example 1 except that (0.004 g as copper ions) was supported by the impregnation method and baked at 400 ° C. During the reaction, the selectivity remained above 99%. The phenol production rate at that time is shown in Table 1.

Example 4 The catalyst used in Example 2 was
It was recalcined in air at 400 ° C., and after calcining, it was molded using a tablet molding machine, crushed, and having a particle size of 1 mm to 710 μm was used as a catalyst. 1 g (2 ml) of the catalyst was packed in a glass reaction tube having an inner diameter of 12 mm, and heat-treated in a mixed gas of helium and oxygen (volume ratio 80/20) at 400 ° C. for 2 hours. Then, after switching to nitrogen gas and lowering the temperature to 350 ° C., the feed rate of the raw materials was reduced as compared with that in Example 2, nitrous oxide was 12 ml / min, benzene was 0.96 g / hr, and nitrogen was 20 ml / min. The reaction was carried out while each was supplied. During the reaction, the selectivity remained above 99%. The production rate of phenol after 1 hour is 73 (gP
hOH / kg-cat / hr), and it was possible to produce phenol with substantially the same level of reaction results as in Example 2.

Comparative Example 2 The catalyst used in Comparative Example 1 was
The reaction was carried out by rebaking and treating in the same manner as in Example 4, but neither conversion nor selectivity was recovered.

Comparative Example 3 Example 1 was repeated except that the amount of gallium ion carried was increased by a factor of 5 in Example 1. The results are shown in Table 1.

Comparative Example 4 Example 3 was repeated except that the amount of copper ions carried was increased by a factor of 5. The results are shown in Table 1.

[0023]

[Table 1]

[0024]

EFFECTS OF THE INVENTION According to the present invention, a phenol can be produced with a high selectivity and a stable yield, a catalyst can be easily produced, and repeated regeneration can be endured. Can be provided.

Claims (2)

[Claims] 1. Reacting benzene and dinitrogen oxide in the presence of a zeolite carrying ions of at least one element selected from the group consisting of elements of Group 3B of the Periodic Table and transition metal elements. And a method for producing phenol. 2. The method for producing phenol according to claim 1, wherein the zeolite is a ZSM-5 type zeolite.